No, voice calls are expressly prohibited in our Terms and Conditions.
T38Fax Incorporated (T38Fax) is a Fax Over IP (FoIP) service provider. We use the T.38 extension of the SIP standard as defined in ITU-T Recommendation T.38 (11/15) to deliver reliable fax transmissions over SIP. This reliability is achieved by converting fax audio signals to T.38 messages which are transmitted as data, instead of audio, thereby avoiding many of the challenges with faxing reliably over SIP trunks. The SIP session’s media is formatted as UDPTL data packets that represent fax procedures instead of having them encoded in RTP audio, and so T.38 fax transmissions between T38Fax and its customers contain no audio, and cannot be used for voice calling.
